Biosynthetic propane can be produced by E. coli bacteria, and potentially photosynthetic bacteria, instead of relying on limited fossil fuels (Photo: Shutterstock)

Propane is an appealing fuel, easily stored and already used worldwide, but it’s extracted from the finite supply of fossil fuels – or is it? Researchers at Imperial College London and the University of Turku have engineered E. coli bacteria that create engine-ready propane out of fatty acids, and in the future, maybe even sunlight.

When considering the bioproduction of fuels, the researchers looked at the alternatives. Propane is cheaper and easier to condense into liquid than other available gaseous fuels, such as hydrogen. And it’s arguably a better synthetic candidate than liquid fuels which can be detrimental to their living bacterial factories and require purification from the host once produced.

With the premise of producing a fuel that’s more sustainable in a biological host and easier to bring to market, the research team engineered a pathway in E. coli that interrupts the conversion of fatty acids into cell membranes and instead couples naturally unlinked enzymatic processes to manufacture propane.

The recently discovered enzyme aldehyde-deformylating oxygenase (ADO) excited scientists because it provided a catalytic step for the production of hydrocarbons, such as propane, but until now hadn’t been successfully manipulated into a synthetic pathway. In this experiment, researchers amped up the catalyzing power of the enzyme by providing extra electrons to the reaction in the form of reducing agents normally present in photosynthetic organisms (E. coli is not photosynthetic; however, cyanobacteria are).

The bacteria were housed in crimped glass tubes to be able to measure the end products for analysis, and as such, there wasn’t a lot of room for storing the propane end product or controlling the concentration of oxygen. Indeed, the researchers observed that with larger vessels and an increased volume of liquid, the propane production continued for up to six times as long, with a two orders of magnitude increase in propane production.

"Although this research is at a very early stage, our proof of concept study provides a method for renewable production of a fuel that previously was only accessible from fossil reserves," said Dr Patrik Jones, from the Department of Life Sciences at Imperial College London. "Although we have only produced tiny amounts so far, the fuel we have produced is ready to be used in an engine straight away. This opens up possibilities for future sustainable production of renewable fuels that at first could complement, and thereafter replace fossil fuels like diesel, petrol, natural gas and jet fuel."

Manufacturing useable quantities of propane is the goal for future expeirments, along with recreating the process in photosynthetic organisms, so that propane could truly be manufactured with the power of sunlight.

Given concerns over limited sources of fossil fuels and concentrations of carbon dioxide, biofuel production has been a promising topic of research, with Gizmag recently seeing bio rocket fuel, and less recently, the production of isobutanol, which can be used to supplement or replace gasoline.

Heidi measures her life with the motley things she's done in the name of scientific exploration. While formally educated in biology and chemistry, informally she learns from adventures and hobbies with her family. Her simple pleasures in life are finding turtles while jogging and obsessively winnowing through her genetic data. All articles by Heidi HoopesFollow @heidihoopes

This may very well be the future of "fossil fuels". Not dug out of the ground, but manufactured from existing natural resources. We'll still have to sequester most of the currently released carbon back underground again, but this new technique means we will be able to use carbon cyclically, rather than the one-way route that fossil fuels send it.

Onihikage 3rd September, 2014 @ 11:55 pm PDT

In future, you will not have to throw away contaminated peanut butter and beef anymore. E. Coli will be your friend.

thk 4th September, 2014 @ 12:48 am PDT

Ah si seulement !

A "true" breakthrough, or another "communication paper" ?

watersworm 4th September, 2014 @ 01:24 am PDT

Fingers crossed that this doesn't get buried along with the many other fossil fuel substitutes we've seen appear then disappear over the decades...

SteveMc 4th September, 2014 @ 01:24 am PDT

Now if we could just get the little buggers to liquify it...

Bob Ehresman 4th September, 2014 @ 08:43 am PDT

Be interesting to see what happens when said E.Coli find their way into the food chain. Brings a whole new meaning to the phrase "explosive diarrhoea"

Aloysius Bear 4th September, 2014 @ 10:42 am PDT

We need a bio-fuel, produced at a low cost, to replace diesel fuel, as the trucking industry is hurting due to the Government and the high cost of fuel.... This country "runs on trucks", and our governments, Federal and States, have made it more and more expensive and difficult, rather than just the opposite. IT'S TIME....

Observer101 4th September, 2014 @ 08:10 pm PDT

@ Bob Ehresman

Propane compresses to liquid at a low enough pressure that the tanks are scarcely heavier than liquid fuel tanks.